What is the difference between a vent valve chamber and a sludge discharge valve chamber?

What is the difference between a vent valve chamber and a sludge valve chamber? I. Their purposes differ
1. Purpose of a vent valve chamber: To facilitate the opening and closing of valves on underground pipelines and conduits (such as water, oil and natural gas pipelines) for operational or maintenance work, a pit (or chamber) resembling a small room is installed.
2. Purpose of a sludge discharge valve chamber: Valves and other components are installed within this chamber to facilitate regular inspection, cleaning and unblocking of pipes, serving as a key point for preventing pipe blockages.

II. Different classifications of components
1. Classification of components in an air vent valve chamber: The classification of components in an air vent valve chamber includes micro air vent valves, composite air vent valves and composite sewage air vent valves.
 2. Classification of components for sludge discharge valve chambers: Hydraulic control valves are valves operated by water pressure. They consist of a main valve and associated components such as guide pipes, pilot valves, needle valves, ball valves and pressure gauges. Depending on their intended use, function and location, these can be adapted into remote-controlled float valves, pressure-reducing valves, slow-closing check valves, flow control valves, relief valves, hydraulic motor-operated control valves, and pump control valves, amongst others.

III. Different Requirements for the Two
1. Requirements for valve chambers: The connection between the chamber shaft, the chamber body and the manhole cover must be reliable; water must not seep into the chamber due to heavy rain or standing water. As valve chambers are buried underground, they must withstand varying pressures from all directions, as well as corrosion and damage from various chemical substances; consequently, they must possess good pressure-bearing capacity and resistance to acid and alkali corrosion.
2. Requirements for sludge discharge valve chambers: The valve chamber itself must be watertight, and its seal integrity must be guaranteed. For valve chambers buried at great depths where the pipework is of a larger diameter, cast iron valves (such as globe valves and butterfly valves) are generally used. As cast iron valves are immersed in water for extended periods, this can affect their service life or lead to fracture; consequently, the requirements for seal integrity are even higher.